Generally speaking, the present invention relates to a timing mechanism which comprises a shaft means, locator means carried by the shaft means, first ramp means coupled to the locator means to position the ramp means in a predetermined position, clutch means coupled to the locator means and the first ramp means, cam means slideably carried on the shaft means and coupling means coupling same to the cam means for rotation therewith, spring means axially biasing the cam means, second ramp means coupled to the cam means and engaging the first ramp means to selectively axially displace the cam means in a predetermined direction, first and second cam followers engaging the cam means to be actuated in accordance with an axial displacement of the cam means, switch means opening and closing in response to movement of the cam followers, and release means permitting the cam means to axially return past the cam followers to its original position.
The invention pertains to a timing mechanism, and more particularly to a timing mechanism wherein there are means for providing a pulse of very short duration prior to an overall program of the timing mechanism.
Timing mechanisms are extensively used in the appliance industry to control the functions of an appliance in accordance with a predetermined program. For example, they are extensively used in washers, dryers, dishwashers, and microwave ovens. In some of these applications the need arises for a short pulsing cycle to be operable within or separate from an overall program. In microwave ovens, for example, such a short pulse is sometimes needed to intermittently apply electrical power to its magnetron. When such power is initially applied to the magnetron, a very high current surge is imposed on the circuit. The surge then drops off. Therefore, there is also a need in this application to provide an even shorter pulse whereby current can be initially switched through a current limiting resistor. The present invention provides a means for achieving short pulses in a very simple and economical manner.